/* Ping))) Sensor original idea from David A. Mellis
 
   This sketch reads a PING))) ultrasonic rangefinder and returns the
   distance to the closest object in range. To do this, it sends a pulse
   to the sensor to initiate a reading, then listens for a pulse
   to return.  The length of the returning pulse is proportional to
   the distance of the object from the sensor.
     
   The circuit:
    * +V connection of the PING))) attached to +5V
    * GND connection of the PING))) attached to ground
    * SIG connection of the PING))) attached to digital pin 12

 */

// this constant won't change.  It's the pin number
// of the sensor's output:
const int pingPin = 12;

//Pin number 13 on the arduino board is linked to the onboard LED. For testing purposes,
//digital pin 1 will be used to display detonation. For demo purposes, this pin can be
//used to create LED circuit.
const int BoomPin = 3;

//This is where the threshold is set. Adjust this value for detonation calibration
const int threshold = 20;

//This is the new Power Pin, please insert the '5V' pin into this slot
const int PowerPin = 5;
int PowerStatus = 1;

//Strongmad put an end to this party
int fuse = 1;

//Internal variable Declorations
long duration, inches, cm;

void setup() {
  // initialize serial communication:
  Serial.begin(9600);
}

void loop()
{
  // establish variables for duration of the ping,
  // and the distance result in inches and centimeters:

  pinMode(BoomPin, OUTPUT);
  digitalWrite(BoomPin, LOW);
  //pinMode(PowerPin, OUTPUT);
  
  //Check the Power Status to see if the Sensor should be transmitting
  //if(PowerStatus == 1){
  //	digitalWrite(PowerPin, HIGH); 
  //}
  //else {
  //	digitalWrite(PowerPin, LOW); 
  //}
  
  // The PING))) is triggered by a HIGH pulse of 2 or more microseconds.
  // Give a short LOW pulse beforehand to ensure a clean HIGH pulse:
  pinMode(pingPin, OUTPUT);
  digitalWrite(pingPin, LOW);
  delayMicroseconds(2);
  digitalWrite(pingPin, HIGH);
  delayMicroseconds(5);
  digitalWrite(pingPin, LOW);

  // The same pin is used to read the signal from the PING))): a HIGH
  // pulse whose duration is the time (in microseconds) from the sending
  // of the ping to the reception of its echo off of an object.
  pinMode(pingPin, INPUT);
  duration = pulseIn(pingPin, HIGH);

  // convert the time into a distance
  inches = microsecondsToInches(duration);
  cm = microsecondsToCentimeters(duration);
 
  Serial.print(inches);
  Serial.print("in, ");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();

  if(inches < threshold){
	if(fuse == 1){
    		Serial.print("MY HEAD EXPLODE!!!");
    		Serial.println();
    		//for(int i=0; i<5; i++){
                for(;;){
	    		digitalWrite(BoomPin, HIGH); 
	    		delay(1000);
	    		digitalWrite(BoomPin,LOW);
	    		delay(1000);
    		}
		fuse = 0;
	}
  }
  
  delay(100);
}

long microsecondsToInches(long microseconds)
{
  // According to Parallax's datasheet for the PING))), there are
  // 73.746 microseconds per inch (i.e. sound travels at 1130 feet per
  // second).  This gives the distance travelled by the ping, outbound
  // and return, so we divide by 2 to get the distance of the obstacle.
  // See: http://www.parallax.com/dl/docs/prod/acc/28015-PING-v1.3.pdf
  return microseconds / 74 / 2;
}

long microsecondsToCentimeters(long microseconds)
{
  // The speed of sound is 340 m/s or 29 microseconds per centimeter.
  // The ping travels out and back, so to find the distance of the
  // object we take half of the distance travelled.
  return microseconds / 29 / 2;
}
